Process for breaking petroleum emulsions



Patented July 29, 1952 PROCESS FOR BREAKING PETROLEUM J EMULSIONS MelvinDe Groote, St. Louis, Mo., assignor to Petrolite Corporation, Ltd.,Wilmington, Del., a corporation of Delaware No Drawing.

Application February 8, 1952,

Serial No. 270,765

9 Claims.

This invention relates to petroleum emulsions of the water-in-oil typethat are commonly re: ferred to as cut oil, roily oil, emulsified 011,

etc., and which comprise fine droplets of nat-v urally-occurring watersor brines dispersed in a more or less permanent state throughout the oilwhich constitutes the continuous phase of the emulsion.

One object of my invention is to provide a novel process for breaking orresolving emulsions of the kind referred to. 7

Another object of my invention is to provide an economical and rapidprocess for separating emulsions which have been prepared undercontrolled conditions from mineral oil, such as crude oil and relativelysoft waters or weak brines. Controlled emulsification and subsequentdemulsification under the conditions just mentioned, are of significantvalue in removing impurities particularly inorganic salts from pipelineoil.

Demulsification as contemplated in the present application includes thepreventive step of commingling the demulsifier with the aqueouscomponent which would or might subsequently become either phase of theemulsion, in absence of such precautionary measure. Similarly, suchdemulsifier may be mixed with the hydrocarbon component. 7

The demulsifying agent employed in the present process is a fractionalester obtained from a polycarboxy acid and a diol obtained by theoxypropylation of 2-methylpentadiol-2,4. Momentarily ignoring certainvariants of structure which will be considered subsequently thedemulsifier may be exemplified by the following formula:

CH3 CH3 in which n and n are numerals including with the proviso that nplus n equals a sum varying from to 80; n" is a whole number not over 2and R is the radical of the polycarboxy acid coon (CO0H)" 2 andpreferably free from any radicals having more than 8 uninterruptedcarbon atoms in a single group, and with the further proviso that theparentdiol prior to esterification be waterinsoluble andkerosene-soluble.

The present application is a continuation-inpart of my co-pendingapplication Serial No. 179,399, filed August 14, 1950, now abandoned.

Attention is directed to the C. M. Blair,-Jr., Patent No. 2,562,878,dated August 7, 1951, the application for which was copending with myapplication Serial No. 179,399 noted above and in which there isdescribed, among other things, a process for breaking petroleumemulsions of the water-in-oil type characterized by subjecting theemulsion to the action of an esterification product of a dicarboxylicacid and a polyalkylene glycol in which the ratio of equivalents ofpolybasic acid to equivalents of polyalkylene glycol is in the range of0.5 to 2.0, in which the alkylene roup has from 2 to 3 carbon atoms, andin which the molecular weight of the product is between 1,500 and 4,000.

Similarly, there have been used esters of dicarboxy acids andpolypropylene glycols in which 2 moles of the dicarboxy acid ester havebeen reacted with one mole of a polypropylene glycol having a molecularweight, for example, of 2,000 so as to form an acidic fractional ester.Examination of what is said subsequently herein as Well as the heretoappended claims incomparison with the previous example will show theline of delineation between such somewhat comparable compounds. Ofgreater significance, however, is what is said subsequently in regard tothe structure of the parent diol as compared to polypropylene glycolswhose molecular weights may vary from 1,000 to 2,000.

For convenience, what is said hereinafter will be divided into fiveparts:

Part 1 is concerned with the preparation of the oxypropylationderivatives of methylpentanediol;

Part 2 is concerned with the preparation of the esters from theoxypropylated derivative;

Part 3 is concerned with a consideration of the structure of the diolswhich is of significance in light of what is said subsequently;

Part 4 is concerned with the use of the products herein described asdemulsifiers for breaking water-in-oil emulsions; and

Part 5 is'concerned with certain derivatives which can be obtained fromthe oxypropylatcd diols. In some instances, such derivatives areobtained by modest oxyethylation preceding the oxypropylation step oroxypropylation followed by oxyethylation. This results in diols havingsomewhat different properties which can then be reacted with the samepolycarboxy acids or anhydrides described in Part 2 to give efiectived.. mulsifying agents. For this reason a description of the apparatusiymalre's casual'mention of oxyethyla'ti'on. For thesame reason there -isbrief mention of the use of glycide.

PART1..

For a number of well'known reasons equip x ment, whether laboratorysize, semi pilotplant size, pilot plant size, or large scale size, 'isnot F as a rule designed for a' particular alkyl'ene Invariably and.inevitably, however, or" particularly in the case of laboratoryequipment and pilot plant size the design is such as to I oxide.

use any of the customarily available alkylene oxide, i. e., ethyleneoxide, propylene oxide,

butylene oxide, glycide,"epichlorohydrin, styrene reaction is higher,speed of reaction is higher, and time of reaction is much shorter. Insuch 7 instances such automatic controls are not necesbe used also gtopermit oiwalliylation involving the use of glycide whereno pressure isinvolved except the vapor pressure of a solvent, if any,

' which may have been used as a diluent.

Oxypropylations are conducted .undera ,wide

variety of conditions, not only in regardlto presence or absence ofcatalyst, and. the *kind of catalyst, butalso in regard to the time of:reaction, temperature of reaction, speed of ,reaction, pressure duringreaction, etc,

peratures up to approximatelyZOO C. withpressures in about the samerange up to about 200 pounds per square inch. They can be conducted IFor instance, oxyalkylations can be conducted at temalso at temperaturesapproximating the boiling point of water, or slightly above, as forexample 95 to 120 C. Under such circumstances the pressure will be lessthan poundspersquare inch unless some special procedure is employed asis sometimes the case, to wit, keeping an atmosphere of inert gas suchas nitrogen in the vessel duringthe-reaction. Such low-temperature-lowreaction rate oxypropylations have been described very completely in U.S. Patent No. 2,448,664 to H. R. Fife, et al,, dated September 7, 1948.oxypropylations are particularly desirablewhere the compound beingsubjected to oxypropylation contains one, two or three pointsof reactiononly, such as monohydric alcohols, glycols and triols.

Sincelow pressure-low temperature reaction speed oxypropylationsrequire'considerable time, for instance, 1, to 7 days 0324 hours each tocomplete the reaction they are conducted as a rule whether ona'laboratory scale, pilot plant scale, or large scale, soas to operateautomatically. The prior figure of seven days applies especially tolarge-scale operations. Ijhave used conventional equipment withtwoladded auto matic features; (a) a solenoid controlled valve whichshuts off the propylene oxide in event that the temperature gets outsidea predetermined and set range, for instance, 95 to 120 (3., and (1))another solenoid valve which shuts off the propylene oxide (or for thatmatter ethylene oxide if it is being used) if the pressure gets beyond apredetermined range, such as 25 to pounds. Otherwise, the equipment issubstantially" the-same as is commonly employed for this purpose wherethe pressureof Low temperature, I low' pressure f having a capacity ofabout one gallon.

.. vAs previously, pointed out the method of using propylene'oxi'de isthe same as ethylene oxide.

This point is emphasized only for the reason thatthe apparatus'is sodesigned and constructed as to use-either oxide.

The-'oxypropylation procedure employed in the -preparation of theoxyalkylated derivatives has (been uniformly the same, particularly inlight of the fact that a continuous automatically controlled procedurewas employed. In this procedure the autoclave was a conventionalautoclave made of stainlesssteel and having a capacity ofapproximately-l5 gallons and a work ing pressure oflone' thousand poundsgauge pressure. .This' pressure obviously is far beyond any requirementas far as propylene oxide jfgoes unless there is a reaction of explosiveviolence involved due to accident. .The autoclave was equipped with theconventional devices and openings, such as-thevariable-speedstirrer-opcrating atspeeds' from 50, R. P. M. to 500R. P. M.;thermometer well and thermocouple for -mechanical thermometer; emptyingoutlet; pressure gauge, manual vent line, charge hole for initialreactants; at least one connection for introducing the alkylene oxide,such as propylene oxide or ethylene oxide, to the bottom of theautoclave; along with suitable; devices .for both cooling .and heatingthe autoclave, such as a cooling jacket, and, preferably, coils inaddition thereto, with. the jacket so arranged that it is suitable .for'heating with steam or cooling with water and further equipped withelectrical heating devices. Such autoclaves are, of course, in

essence, small-scale replicas of the usual conventional autoclave usedin oxyalkylation procedures. .In some instances in exploratorypreparations an autoclave having a smaller capacity, for instance,approximately 3 liters in one case and about 1% gallons in another case,was used.

Continuous operation, or substantially continuous operation, wasachieved by the use of a separate container to hold the alkylene oxidebeing employed, particularly propylene oxide. In conjunction withthesmaller autoclaves, the container consists essentially of a laboratorybomb having a capacity of about one-half gallon, or somewhat in excessthereof. In some instances a larger bomb was used, to wit, one This bombwas equipped, also, with an inlet for charging, and an eductor tubegoing to the bottom of the container so as to permit discharging ofalkylene oxide in the liquid phase to the autoclave. A bomb having acapacity of about pounds was used in connection with the 15 gallonautoclave. "Other conventional equipment consists, of course, of therupture disc, pressure gauge, sight feed glass, thermometer, connectionfor nitrogen for pressuring bomb, etc. The bomb was placed on a scaleduring use. The con- 'no solvent such as xylene is employed.

nections between the bomb and the autoclave were flexible stainlesssteel hose or tubing so that continuous weighings could be made withoutbreaking or making any connections. This applied also to the nitrogenline, which was used to pressure the bomb reservoir. To'the extent thatit was required, any other usual conventional procedure or additionwhich provided greater safety was used, of course, such as safety glass,protective screens, etc.

Attention is directed again to what has been said previously in regardto automatic controls which shut off the propylene oxide in eventtemperature of reaction passes out of the predetermined range or ifpressure in the autoclave passes out of predetermined range.

With this particular arrangement practically all oxypropylations becomeuniform in that the reaction temperature was held within a few degreesof any selected point, for instance, if.

105 C. was selected as the operating tempera ture the maximum pointwould be at the most 110 C. or 112 C., and the lower point would be 95or possibly 98 C. Similarly, the pressure was held at approximately 30pounds within a 5-pound variation one way or the other, but might dropto practically zero, especially where The speed of reaction wascomparatively slow under such conditions, as compared withoxyalkylations at 200 C. Numerous reactions were conducted in which thetime varied from one day (24 hours) up to three days (72 hours), forcompletion of the final member of a series. In some instances thereaction may take place in considerably less time, i. e., 24 hours orless as far as partial oxypropylation is concerned. The minimum timevrecorded was about a 3-hour period in a single step, but usually was 6hours. Reactions indicated as being complete in 7 hours may have beencomplete in a lesser periodof time in light of the automatic equipmentemthat ifthe reaction was interrupted automatically for a period of timefor pressure'to drop or temperature to drop the predetermined amount ofoxide would still be added inmost instances well within' thepredetermined time period. Sometimes where the additionwas acomparatively small amount in an 8-hour period there would be anunquestionable speeding up of the reaction by simply repeating theexample and using 4, 5, or 6 hours instead of 8 hours.

When operating at a comparatively high temperature, for instance,between 150 and 200 C., an unreacted alkylene oxide, such as propyleneoxide, makes its presence felt in the increase in pressure or theconsistency of a high pressure. However, at a low enoughtemperatureiomay happen that the propylene oxide goes in as liquid. Ifso, and if it remains unreacted there is, of course, an inherent dangerand appropriate steps must be taken to safeguard against thispossibility; if need be a samplemust be withdrawn and examined forunreacted propylene oxide. One obvious procedure, of course, is tooxypropylate at a modest y higher temperature, for instance, at 140 to150 C. Unreacted oxide affects determination of the) acetyl or hydroxylvalue of the hydroxylated compound obtainedt" The higher the molecularweight of thechompound, i. e., towards thelatter stages of reaction, thelonger the time'required to add a given amount of oxide. One possibleexplanation is" that the'molecule, being larger, the opportunity forrandom reaction is decreased. 'Inversely, the lower the molecular weightthe faster the reaction takes placeff For this rea'sonfsometimes atleastjincreasing the concentration of the catalyst does not"appre'ciably' speedup the reaction, particularly when the productsubjected to oxyalkylation has a comparatively high molecular weight.However, as has been pointed out previously, operating at a low pressureand a low temperature even'in large scale operations as much as a weekor. ten days time may lapse to obtain some of the higher molecularweight derivatives from monohydric or dihydrio materials.

. In a number of operations the counterbalance scale or dial scaleholding the propylene oxide bomb was so set that when the predeterminedamountof propylene'oxide had passed-into thereaction the scale movementthrough a time operating device was set for either one to two hourssothat reaction continued for l to 3 hours after the final addition ofthelast propylene oxide and thereafter the operation was shutdown. Thisparticular device is particularly suitable for use on larger equipmentthan laboratory size autoclaves, to wit, on semi-pilot plant or pilotplant size, as well as on large scale size. This final stirring periodis --intended to avoid the presence of unreacted oxide; 7

-In this sort of operation, of course, the temperature range wascontrolled'automatically'by either use of cooling water,steam,-or=electrical heat, so as to raise or lower the temperature. Thepressuring of the propylene oxide into the reaction-vessel was alsoautomatic insofar that the feedstream was set for a slow continuous runwhich was shut off in case the pressure passed a predetermined point aspreviouslyset out. "All the points of design construction,'etc.,. wereconventional including the gases, check valves and entire equipment. Asfar as I am aware at least twofirms, and possibly three, specialize inautoclave equipment such as I have employed in the laboratory, and areprepared to furnish equipment of this same kind. Similarly, pilot plantequipment is available. This pointissimply made as a precaution in thedirection of safety. Oxyalkylations, particularly involving ethyleneoxide, glycide. propylene oxide, etc., should not be conducted except inequipment specifically designed for the purpose.

Example 1a The particular autoclave employed was one with a capacity ofapproximately 15 'gallonsor on the average of about pounds of reactionmass. The speed of the stirrer could be varied from to 340 R. P. M. 6.6pounds of Z-methyl- 2,4-pentanediol were charged into the autoclavealong with two-thirds of a' pound of sodium hydroxide. The reaction potwas flushed out with nitrogen. The autoclave was sealed, the automaticdevices adjusted, and set for injecting a total of about 57% pounds ofpropylene oxide in a 6 hour period. The pressure regulator :was set fora maximum of 35 pounds per square inch. Thismeant that the bulk of thereaction could take place, and probably did take place, at a duction ofpropylene oxide was not started until the heating devices had raised thetemperature to approximately the boiling point of water. At thecompletion of the reaction a sample was taken and oxypropylationproceeded as in Example 2a, immediately succeeding.

' Example 2a .Slightly over 56.5-pounds of the reaction mass identifiedas Example 1a, preceding, were permitted to remain in the regular vesseland without the addition of any more catalyst approximately 26 pounds ofpropylene oxide were added. The oxypropylation was conducted insubstantially the same manner in regard to pressure and temperature asin Example 1a, preceding, except that the reaction period was completedin slightly less time, i. e., 6 hours, and the maximum temperature at notime exceeded 99 C., i. e., just short of the boiling point of water.end of the reaction period part of the sample was withdrawn andoxypropylation continued a described in Example 3a, following.

Example 3a Approximately 44.4 pounds of the reaction mass identified asExample 2a, preceding, were permitted to stay in the reaction vessel and19.25 pounds of propylene oxide were introduced during this thirdperiod. No additional catalyst was added. The-conditions of reaction, asfar as temperature and pressure were concerned, were substantially thesame as in Example la, preceding. The reaction time was approximatelythe same as in the two earlier periods, i. e., 6% hours. During thisparticular period again the .temperature stayed below the boiling pointof water, i. e., 99C. maximum. At the completion of the reaction, partof the reaction mass was withdrawnand the remainder subjected tooxypropylation as'described in Example 4a, succeeding.

Example 4a Approximately 56 pounds of the reaction mass were permittedto remain in the autoclave. No additional catalyst was added.Approximately 23.7 pounds of propylene oxide were introduced in the samemanner as described in Example 1a, preceding. Conditions in regard totemperature did not reach the boiling point of water, i. e., was below100 C. The timeperiod was slightly longer than in the three earlierstages, i. e., 7 hours. In this stage and, as a matter of fact, in allthe stages, there was no pressure beyond 30 pounds per square inch atany time. At the end of the reaction period part of the sample waswithdrawn and the remainder of the reaction mass Was-subjected tofurther oxypropylation as described in Example a, succeeding.

Example '51;

At the The procedure was the same as inExample 1a and other precedingexamples; and the conditions of temperature.and pressure weresubstantially the same. The time required to introduce the oxide was 7hours.

What has been said herein is presented in tabular form in Table 1immediately following, with some added information as to molecularweight and as to solubility of the reaction product in xylene andkerosene.

TABLE 1 Composition Before Composition at End Ex. N0. H. 0. Oxide Catal-Theo. H. 0. Oxide Cata:

Amt. Amt. lyst M01. Amt. Amt. lyst Lbs. Lbs. Lbs. Wt. Lbs. Lbs. Lbs.

1 The hydroxylatcd compound is 2-methyl-2,4- pentanediol.

4 Max.

Max.

Pres. Time E o r lbs. sq. Hrs.

Examples 1a through 5a, inclusive, were all insoluble in Water, butsoluble in xylene, and soluble in kerosene.

The final product, i. e., at the end of the oxypropylation step, was asomewhat viscous very pale straw-colored fluid which waswater-insoluble. This is characteristic of all various end productsobtained in this series. These products were, of course, slightlyalkaline due to the residual caustic soda employed. This would also bethe case if sodium methylate were used as a catalyst.

Speaking of insolubility in water or solubility in kerosene suchsolubility test can be made simply by shaking small amounts of thematerials in a test tube with water, for instance, using 1% to 5%approximately based on the amount of water present.

Needless to say, there is no complete conversion of propylene oxide intothe desired hydroxylated compounds. This is indicated by the fact thatthe theoretical molecular weight based on a statistical average isgreater than the molecular weight calculated by usual methods on basisof acetyl or hydroxyl value. Actually, there is no completelysatisfactory method for determining molecular weights of these types ofcompounds with a high degree of accuracy when the molecular' weightsexceed 2,000. In some instances the acetyl value or hydroxyl valueserves as satis factorily as an index to the molecular weight as anyother procedure, subject to the above limitations, and especially in thehigher molecular weight range. If any difficulty is encountered in themanufacture of the esters as described in Part 2 the stoichiometricalamount of acid or acid compound should be taken which corresponds to theindicated acetyl or hydroxyl value. This matter has been discussed inthe literature and is a matter of common knowledge and reacids having 18carbon atoms.

5: quires no further elaboration. In fact, it is illustrated by some ofthe examples appearing in the patent previously mentioned.

PART 2 As previously pointed out the present invention is concerned withacidic esters obtained from the oxypropylated derivatives described inPart glycollic acid, sebacic acid, azelaic acid, aconitic acid, maleicacid or anhydride, citraconic acid or anhydride, maleic acid oranhydride adducts as obtained by the Diels-Alder reaction from re-Tactants such as maleic anhydride and cyclopentadiene. Such acids shouldbe heat stable so they are not decomposed during esterification.

They may contain as many as 36 carbon atoms as,

for example, the acids obtained, by dimerization-j;

of unsaturated fatty acids, unsaturated monocarboxy fatty acids, orunsaturated monocarboxy Reference to. the acid in the hereto appendedclaims obviously includes the anhydrides or any other obviousequivalents.

My preference, however, is .to use polycarboxy acids having not over 8carbon atoms.

The production of esters including acid esters (fractional esters) frompolycarboxy acids and glycols'or other hydroxylated compounds is wellknownr Needless to say, various compounds may be used such as the lowmolal ester, the anhydride, the acyl chloride, etc. However, for purposeof economy it is customary to use either the acid or the anhydride. Aconventional procedure is employed. On a laboratory scale one can employa resin potof the-kind described inU. S. Patent No. 2,499,370,datedMarch'Z, 1950 to De Groote and Keiser, and'particularly with onemore opening to permit the use of a porous spreader-if hydrochloric acidgas is to be used as a catalyst. Such device or absorption spreaderconsists of minute Alundum thimbles which are connected to a glass tube.One can add a sulfonic acid such as para-toluene sulfonic acid as acatalyst. There-is some objection to this .because in some instancesthere is some evidence that this acid catalyst tends to decompose or re-10 tostand overnight It' is then filtered and refluxedwith the-xylenepresent until the wat'e'r can be separatedin a fphase-separatingtrap'. As ,soon as the product 'is substantially free from .water thedistillation stops. Thisprelimin'ary step can be cameaourm the'flask .tobe" used for esterification. Ifthere' is any further deposition ofsodium chloride during 'the' reflux stage needless to saya secondfiltration may be required. In anyv event the neutral orrslightly acidicsolution of the oxypropylated derivatives described in Part 1 is thendiluted further with sufficient xylene klecalin, petroleumsolvent, orthe like so that one has obtained approximately a 65% solution. Io thissolution there. is added a polycarboxylatedlreactant asvpreviouslydescribed, such as phthalic anhydride, succinic acid or'anhydride; diglycollic acid, .etc. The mixture is refluxed untilesterification is complete as indicated by elimination of water or'dropin carboxyl value' Needless to say, if one-produces a half-ester from ananhydride-such as "phthalic anhydride, ,'no' water is eliminated.

However, if it' is obtained from'diglycollic acid, for example, water iseliminated'; All suchprocedures are conventional and have been" sothoroughly described iin'the' literature that further consideration willbe limited to a few examples and a comprehensive table. a

Other procedures for eliminating the basic residual catalyst, if any,can be employed.- "For example, the oxyalkylation can be conducted'inabsence of a solvent or the solvent removed after oxypropylation. Suchoxypropylation end productcan then be acidified 'with -just enoughconcentrated hydrochloric acid to just neutralize the residualbasic'catalyst. -To this product one can then. add' a small amountof-anhydrous sodium for. esterification in the mannerdescribedcreasonably convenient means available of remov';

ing the paratoluene sulfonic acid or other s'ul ionic acid employed. Ifhydrochloric acid is employed one need only pass the gas through at *1an exceedingly slow rate so as to keep thereac tion mass acidic. Only atrace of acidneed be' present. I have employed hydrochloric acid gas vor the aqueous acid itself to eliminate theinitial basic material. Mypreference, however, is to use" no catalyst whatsoever and toinsurecomplete dryness of the diol as described in the finalproe cedurejust preceding Table 2.

The products obtained in Part 1 preceding may contain a basic catalyst.Asa general procedure 1 I have added an amount of half-concentratedhydrochloric acid considerably in excess of what is required toneutralize the residual catalyst; The mixture is shaken thoroughly andallowed Itis to'be pointed'out that the products here described are notpolyesters fin the sense that there is a plurality of bothdiol'radicalsand acid radicals; the product is characterized byhavingonly one diol radical.

In some instances and, in fact, in many in- .stances I have found thatin spite of the dehy- ,-drjation methods employed above that a meretrace of water still comes through and that this mere trace of watercertainly interferes with the acetyl or hydroxyl value determination, atleast i when a number of conventional procedures are used, and mayretard esterification, particularly Where there is no sulfonic acid orhydrochloric acid presentlas a catalyst. Therefore, I have preferred touse the following procedure: I have employed about 200: grams of thediol as described in Part 1, preceding; I have added about grams ofbenzeneQand then refluxed this mixture inthe glass resin potusing aphase-separating trap until the benzene carried out all the waterpresentas water of solution or the equivalent. Ordinarily this refluxingtemperature 'is apt to be in the neighborhood of to possibly C. When allthis water or moisture has I. B. P., 142C.

. ii also about 150 grams of a highboiling aromatic petroleum "solvent.These solvents are sold by various oil refineries and,'as far as solventeffect act as if they were almost completely aromatic in character.Typical distillation data in'the particular type I have employed andfound very satisfactory is the following:

5 ml.,'200 C. ml., 244 C. 10 ml., 209 C. ml., 248 C. 15 ml., 215 C. ml.,252 C. 20 ml., 216 C. ml., 252 C. 25 ml., 220 C. ml., 260 C. 30 ml.,225" C. ml., 264? C. 35 ml.,. 230 C. ml., 270 C. 40 ml., 234 C. ml.,230? C. 45 ml., 237 C. ml., 307 C.

After, this material is added, refluxing is continued and, of course, isat a high temperature, to wit, about to C. If the carboxy reactant is ananhydride needless to say no water of reaction appears; if the carboxyreactant is an acid, water of reaction should appear and should beeliminated at the above reaction temperature. If it is not eliminatedI'simp'ly separate out another 10 or20 cc. of benzene by means of thephase-separating trap and thus raise the temperature to or C.,'or evento 200 C.,

if need be. My preference is not to go above about 200 C.

The use of such solvent is extremely satisfactory providedone does notattempt to remove the solvent subsequently except by vacuum distillationand provided there is no objection to a little residue. Actually, whe'nthese materials are used fora purpose such as demulsification thesolvent might just as-well be allowed to remain. If the solventis to beremoved by distillation, and particularly vacuum distillation,-thenthe-high boiling aromatic petroleum solvent might well be replaced bysome more expensive solvent, such as decalin or an alkylated decalinwhich has a rather definite or close range boiling point. The removal ofthe solvent, of course, is purely a conventional procedure and requiresno elaboration.

The data included in the subsequent tables, 1. e., Tables 2 and 3, areself-explanatory, and very complete and it is believed no further elabo-TABLE 3 Ex. No. Amt. Esterifi- Time of Water Acid Solvent Solvent cationEsterifica- Out Ester (grs) 'lemp., C. tion (Hrs) (cc.)

1b Solvent 7-3.... 240' 147 3 6.0

251 154 3 None 234 155 3 None 254 191 2% 5. 8 234 171 2% None 230 149 34. 7 249 170 3% None 226 170 3 None 241 200 5% 4. 2 230. 166 3% None 227174 3% 4.1 234 166 3% None 224 150 3% None 236 152 3% 4.1 226 151 3% 0.5 222 151 3% 3.3 227 150 5 None 218 132 3 None 229 181 3 3. 2 221 160 2%None 220 174 2% 3. 2 226 153 2 None 217 155 2 None 220 155 2 one 228 1585 3. 1

Note.In foregoing Tables 2 and 3, with particular reference to Table 3,the solvent used was one which has been indicated for convenience asSolvent 7-3. This was a mixture of 7 volumes of the petroleum solventpreviously described and three volumes of benzene. This, or-esimilarmixture, was used in the manner previously described. 'Actaully sampleshave been prepared using decalin instead of the latter mixture orothersolvents. If one does not intend to remove-the solvent subsequentlymy preference is to use theaboveml xture, i. e., Solvent 7 3, and usethe benzene to give initial dehydration as previously described.Incidentally, other comparable mixtures, such as a mixture of decalinand xylene, can be employed.

The procedure for manufacturing the esters has been illustrated bypreceding examples. If for any reason reaction does not takeplace in amanner that is acceptable, attention should be directed to the followingdetails: (a) Recheck the hydroxyl 0'1 acet'yl value of the oxypropylateddiol and use a stoichiometrieally equivalent amount of acid; (b) if thereaction does not proceed with reasonable speed either raise thetemperatures indicated or else extend the period of time up to 12 or 16hours if "need be; (c) if necessary, use of'paratoluene sulfonicacid orsome other acid asa catalyst; ('d) if the esterification does notproduee'a clear product a check should be made to see if an inorganicsalt such as sodium chloride or sodium'sulfate is not preratlon isnecessary. 50 cipitatmg out. Such salt should be eliminated,

TAB-LE 2 M01 Theo. "Amt. of

E; N 'Weight mt. of IE 9- f Hyg Theo" Actual Based Hyd. Polycarboxy PolyQfig droxy fi y 011 r nd. Reactent 35 3 Cmpd. O yl Value yifitllral(grs.) ant 1, 150 97. 5 98. 4 1, 140 200 Diglycollic Acid... 47 1, 15097. 5 98. 4 1, 140 200 Phthalic Anhyd- 51. 8 1,150 97. 5 98. 4 1, 140200 Maleic Anhyd. 34:3 1, 150 97. 5 98'. 4 1, 140 200 Aconitie Acid. 61.0 1, 150' 97. 5 9B. 4 l, 140 200 Citraconic Aeid.-' 39. 2 l, 670 67. 173. 9 1, 516 200 Diglycollic Acid... 35,4 1, 670 67. 1 73. 9 1, 516 200Phthalic Anhyd... 39. 2 ,670 67. 1' 73(9 1, 516 200 Maleic Anhyd 25.-91', 670 67. 1 73. 9 1, 516 200 Aconitic Acid. 48. 0 1, 670 67. 1 73. 91, 516 200 Citraconic Aoid 30. 1 2, 400 46:6 63. 7. 1, 760 200Diglycollio Acid...- 30.5 2, 400 46. 6 63. 7 l, 760 200 PhthalicAnhyd-.. '33. 8 2, 400 40. 6 63. 7 1, 700 200 Maleio .Anhyd- 22. 4 2,400 45. 6 63. 7 1, 760 200 Aconitic Acid. 39. 7 2, 400. 46; 6 63. 7, l,760 200 Citreconic Acid- 25. 3 3, 440 32. 5 51. 2 2, 184 200 DiglycollicAcid.-. 24. 4 a, 440 32; 5 a1. 2 2,184 200 Phthalic Anhyd. 27.1 3, 44032. 5' 51. 2 2, 184 200 Maleic Acid l8. 0 3, 440 32. 5 51. 2 2, 184 20Aconitic'Aeid 31; 8 3, 440 32. 5 51. 2 2, 184 20 Citra'conic Acid..- 20.5 4, 430. 25. 3 48. l 2, 2 80 200 Diglycollic Acid... 23. 4 4, 430 25.348. 1 2, 280 w 200 Phthalic Anhyd. 25. SJ 4, 430 25. 3 48.1 2, 280 200Meleic Aci 17. 1 4, 430 3 48. 1 2, 280 200 Cltraconic Acid 19. 6 4, 43025.3 48.1 2, 280 200 Aconitic'Acid. M 30.4

.113 at least for exploration experimentation, and can be removed byfiltering. Everything else bein equal as the size of the moleculeincreases the reactive hydroxyl radical represents a smaller fraction ofthe entire molecule and thus more dif-.

ficulty is involved in obtaining complete esterification,

Even under the most carefully controlled conditions of oxypropylationinvolving comparatively low tempertaures and long time of reaction thereare formed certain compounds whose composition is still obscure. Suchside reaction products can contribute a substantial proportion of thefinal cogeneric reaction mixture. Various suggestions have been made asto the nature of these compounds, such as being cyclic polymers ofpropylene oxide, dehydration products with the appearance of a vinylradical, or isomers of propylene oxide or derivatives thereof, i. e., ofan aldehyde, ketone or alcohol. In some instances an attempt to reactthe stoichiometric amount of a polycarboxy acid with the oxypropylatedderivative results in an excess of the carboxylated reactant for thereason that apparently under conditions of reaction less reactivehydroxyl radicals are present than indicated by the hydroxyl value.Under such circumstances there is simply a residue of the carboxylicreactant which can be removed by filtration or, if desired, theesterification procedure can be repeatedusing an appropriately reducedratio of carboxylic reactant.

Even the determination of the hydroxyl value and conventional procedureleaves much to be desired due either to the cogeneric materialspreviously referred to, or for that matter, the presence of anyinorganic salts or propylene oxide. Obviously this oxide should beeliminated.

The solvent employed, if any, can be removed from the finished ester bydistillation and particularly vacuum distillation, The final products orliquids are generally pale amber to amber in color, and show moderateviscosity. They can be bleached with bleaching clays, filtering chars,and the like. However, for the purpose of demulsification or the likecolor is not a factor and decolorization is not justified.

In the above instances I have permitted the solvents to remain presentin the final reaction mass. In other instances I have followed the sameprocedure using decalin or a mixture'of decalin or benzene in the samemanner and ultimately removed all the solvents by vacuum distillation.Appearances of the final products are much the same as the diols beforeesterification and in some instances were somewhat darker in color andhad a reddish cast and perhaps somewhat more viscous.

PART 3 Previous reference has been made to the fact that diols such aspolypropyleneglycol of approximately 2,000 molecular weight, forexample, have been esterified with dicarboxy acids and employed asdemulsifying agents. On first examination the diflfference between theherein described products and such comparable products appears to berather insignificant. In fact, the difference is such that it fails toexplain the fact that compounds of the kind herein described may be, andfrequently are, or better on a quantitative basis than the simplercompound previously described, and demulsify faster and give cleaner oilin many instances. The method of making such comparative tests has beendescribed in a booklet entitled Treating ,14 Oil Field Emulsions, usedin the Vocational Training Courses, Petroleum Industry Series, of theAmerican Petroleum Institute.

The difference, of course, does not reside in the carboxy acid but inthe diol. Momentarily an effort will be made to emphasize certain thingsinregard to the structure of a polypropylene glycol, such aspolypropylene glycol of a 2000 molecular weight. Propylene glycol has aprimary alcohol radical and a secondary alcohol radical. In this sensethe building unit which forms polypropylene glycols is not symmetrical.Obviously, then, polypropylene glycols can be obtained, at leasttheoretically, in which two secondary alcohol groups are united or asecondary alcohol group is united to a primary alcohol group,etherization being involved, of course, in each instance.

.Usually no effort is made to differentiate between oxypropylationtaking place, for example, at the primary alcohol unit radical or thesecondary alcohol radical. Actually, when such products are obtained,such as a high molal polypropylene glycol or the products obtained inthe manner herein described one does not obtain a single derivative suchas HO'(RO)nH in which n has one and only one value, for instance, 14, 15or- 16, orthe like. Rather, one obtains a cogeneric mixture of closelyrelated or touching homologues. These materials invariably have highmolecular weights and cannot be separated from one another by any knownprocedure without decomposition. The properties of such mixturerepresent the contribution of the various indi vidual members of themixture. On a statistical basis, of course, n can be appropriatelyspecified. For practical purposes one need only consider theoxypro-pylation of a monohydric alcohol because inessence this issubstantially the mechanism involved. Even in such instances where oneis concerned with a monohydric reactant one cannot draw a single formulaand say that by following such procedure one can readily obtain or or ofsuch compound. However, in the case of at least monohydric initialreactants one can readily draw the formulas of a large number ofcompounds which appear in some of the probable mixtures or can beprepared as components andmixtures which are manufacturedconventionally.

Simply by way of illustration reference is made to the De Groote, Wirteland Pettingill Patent No. 2,549,434, dated April 17, 1951, theapplication for which was copending withmy copending application SerialNo. 179,399, noted above.

However,, momentarily referring again to a monohydric initial reactantit is obvious that if one selects any such simple hydroxylated compoundand subjects such compound to oxyalkylation, such as oxyethylation, oroxypropylation, it becomes obvious that one is really producing apolymer of the alkylene oxides except for the terminal group. This isparticularly true where the amount of oxide added is comparativelylarge, for instance, 10, 20, 30, 40 or 50 units. If such compound issubjected to oxyethylation so as to introduce 30 units of ethyleneoxide, it is well known that one does not obtain a single constituentwhich, for the sake of convenience, may be indicated as RO (C2H4O) 30H.Instead, one obtains a cogeneric mixture of closely related homologues,in which the formula may be shown amount may vary from instances where nhas a value of 25, and perhaps'less, to a point where 11. may representor more. Such mixture is, as stated, a cogener-icclosely related seriesof touching homologouscompounds. Considerable investigation has beenmade in regard to the distribution curves for linear polymers. Attentionisdirected to the article entitled Fundamental Principles ofCondensation Polymerization, by Flory, which appeared in ChemicalReviews, volume 39, No. 1-, page 137. A

Unfortunately, as has been pointed out by Flory and other investigators,there is no satisfactory method, based on either experimentalormathematical examination, of indicating the exact proportion of thevarious members .of touching homologous series which appear in cogenericcondensation products of the kind described. This means that from thepractical standpoint, i. e., the ability to describe how to make theproduct under consideration andhow to repeat such production time aftertime without difficulty, it is necessary to resort to some other methodof description, or else consider the value of n,.in formulas such asthose which have appeared previously and which appear in the claims, asrepresenting both individual constituents in which n has a singledefinite value, and also with the understanding that n represents theaverage statistical value based on the assumption of completeness ofreaction. Y

This may be illustrated as follows: Assume that in any particularexample the molal ratio of the propylene oxide to the diol is 15 to 1,Actually, one obtains products in which it probably varies from 10 to20, perhaps even further. The average value, however, is 15, assuming,as previously stated, that the reaction iscomplete. The productdescribed by the-formula is best described also in terms of method ofmanufacture.

However, in the instant situation it becomes obvious that if an ordinaryhigh molal propyleneglycol is compared to strings of white beads ofvarious lengths, the diols herein employed as intermediates arecharacterized-by the presence of a black bead, i. e., a radical whichcorresponds to 2-methylpentanediol-2,4, i. e., the radical Furthermore,it becomes obvious that one now has a nonsyrrimetrical radical-inthe'majority of cases for the reason that in the-cogeneric-mixture goingback-to theioriginal" formula l I I CH3 CH3 0 i O n'and n arejus'uallynot equal. For instance, if one introduces 15 moles of propylene oxide,n and n could not be equal, insofar that the nearest approach toequality is wherethe'value of 1i is land n'is 8. However, even inthecaseof an even number such as 20, '30, 40' or 50, itis also obviousthat n and n will not be equal in light of what has been saidpreviously. Both sides of the molecule are not going to grow with equalrapidity, i. e., to the same size. Thus the diol herein employed isdifferentiated from polypropylene diol 2000, for'exa'mple, in that (a')it carries a hereto unit, i. e., a unit other than a propylen'eglycol orpropylene oxide unit, (b) such unit is off center,.and (c) the effect ofthat unit, oflcourse, must have some effect in the range with which thelinear molecules can be drawntogether by hydrogen binding or van derWalls forces, or Whatever else may be involved.

What has been said previously can be emphasized in the following manner.It has been pointed out previously that in the last formula immediatelypreceding, 1 or n could be zero. Under the conditions of manufacture asdescribed in Part 1 it is extremely unlikely that n is ever zero.However, such compounds can be prepared readily with comparativelylittle difficulty by resorting to a blocking effect or reaction. Forinstance, if the 2-methylpentanediol-2,4 is esterified with a low molalacid such as acetic acid mole for mole, and such product subjected tooxyalkylation using a catalyst, such as sodium methylat and guardingagainst the presence of any water, it becomes evident that all thepropylene oxide introduced, for instance 15 to molecules per polyhydricalcohol molecule.

necessarily must enter at one side only. If such product is thensaponified so as to decompose the acetic acid ester and then acidifiedso as to liberate the Water-soluble acetic acid and the water-insolublediol a separation can be made and such diol then subjected toesterification as described in Part 2, preceding. Such esters, ofcourse, actually represent products where either 21. or n is zero. Also'intermediat procedures can be employed, i. e.,-following the sameesterification step after partial oxypropylation. For instance, onemight oxypropylate with one-half the ultimate amount of propylene oxideto be used and then stop the reaction. One could then convert thispartial oxypropylated intermediate into an ester by reaction of one molof' acetic acid with one mole of a diol. This ester could then beoxypropylated with all the remaining propylene oxide. The final productso obtained could be saponified and acidified so as to elimi- 1 nate'thewater-soluble acetic acid and free the obviously unsymmetrical diolwhich, incidentally, should also be kerosene-soluble.

From a practical standpoint I have found no advantage in going to thisextra step but it does emphasize the difference in structure between theherein described diols employed as intermediates and high molalpolypropylene glycol, such as polypropylene glycol 2000.

FART 4 Conventional demulsifying agents employed in the treatment of oilfield emulsions are used as such, or after dilution with any suitablesolvent,

such as water, petroleum hydrocarbons, such as benzene, toluene, Xylene,tar acid oil, cresol, anthracene oil, etc. Alcohols, particularlyaliphaticalcohols, such as methyl alcohol, ethyl alcohol, denaturedalcohol, propyl alcohol, butyl alcohol, hexyl alcohol, octyl alcohol,etc, may be employed as diluents'. Miscellaneous solvents such as pineoil, carbon tetrachloride, sulfur dioxide extract obtained in therefining of petroleum, etc., may be employed as diluents. Similarly, thematerial or materials employed as the demulsifying agent of my processmay be admixed with one or more of the solvents customarily used inconnection with conventional demulsifying agents. Moreover, saidmaterial or materials may be used alone or in admixture with othersuitable well-known classes of demulsifying agents. I

It is well known that conventional demulsifying agents may be used in awater-soluble form, or in an oil-soluble form, or in a form exhibitingboth oiland water-solubility. Sometimes they may be used in a form whichexhibits relatively I limited oil-solubility. However; since suchreagents are frequently used in a ratio of l to 10,000 or I to 20,000,or 1 to 30,000, or even 1 to 40,000, or 1 to 50,000 as in desaltingpractice, such an apparent insolubility in oil and water is notsignificant because said reagents undoubtedly have solubility withinsuch concentrations. This same fact is true in regardto the material ormaterials employed as the demulsifyingagent, ofHmy process. v

In practicing my process for resolving petro -e leum emulsions of thewater-in-oil type, a treating agent or demulsifying agent ofcthe kindabove described is brought into contact withor caused to'act upon theemulsion to be treated, in any of the various apparatusnow generallyused to resolve or break petroleum emulsions with a chemical reagent,the above procedure being used alone or in combination withotherdemulsifying procedure, such as the electrical dehydration process.

One type of procedure is to accumulate a volume of emulsified oil in atank and conduct a batch treatment type of demulsification procedure torecover clean oil, In this procedure the emulsion is admixed with thedemulsifier, for example by agitating the tank of emulsion and slowlydripping demulsifier into the emulsion. In some cases mixing is achievedby heating the emulsion while dripping in the demulsifier, dependingupon the convection currents in the emulsion to produce satisfactoryadmixture. In a third modification of this type of treatment, acirculating pump withdraws emulsion from, e.- g., the bottom of thetank, and reintroduces it into the top of the tank, the demulsifierbeing'added, for example, at the suction side of said circulatingpump. I

a second type of treating procedureQthe demulsifier is introduced intothe well fluids, at the well-head or at some point between the Well headand the 'final oil storage tank, by means of an adjustable proportioningmechanism or proportioning pump. Ordinarily the flow of fluids throughthe subsequent lines and fittings suffices to produce the desired degreeof mixing of demulsifier and emulsion, although in some instancesadditional mixing devices may be introduced into the flow system. Inthis general procedure, the system may include various mechanicaldevices for withdrawing free water, separating entrained water, oraccomplishing quiescent settling of the chemicalized emulsion. Heatingdevices may likewise be incorporated in any of the treating proceduresdescribed herein.

A third type of application (down-the-hole) of demulsifier to emulsionis to introduce the demulsifier either periodically or continuously indiluted or undiluted form into the Well and to allow it to come to thesurface with the well fluids, and then to flow the ch'emicalizedemulsion through any desirablesurface equipment, such as employed in theother treating procedures- This particular type of application-isdecidedlyuseful when the demulsifier is'used. in. connection withacidificationf calcareous oil-bearing strata, especially if suspended inor dissolved inthe acid employed foracidificationl 3 In all cases, itwill be 'apparentfrom the foregoing description, the broad processconsists simply in introducing a relatively small proportion ofdemulsifier into a relatively large proportion of emulsion, admixing thechemical and emulsion either through natural fiow'or through specialapparatus, with or without the application of heat, and allowing themixture to stand quiescent until the undesirable water content of .theemulsion separates and settles from the mass.

The following is a typical installation.

A reservoir-to hold the 'demulsifier of the kind described (diluted orundiluted) is placed at the well-head where the effiuent liquids leavethe well. This reservoir or container, which may vary from 5 gallonsto50 gallons for convenience, is connected'to a proportioning pump whichinjects the demulsifier drop-wise into the fluidsv leaving the well.Such chemicalized fluids pass through the flowline into a settling tank.The settling tank'consists of a tank of any convenient size, forinstance, one which will hold amounts of fluid produced in 4 to 24 hours(500 barrels to 2000 barrels capacity), and in which there is-agperpendicular conduit from the top of the tank to almost the verybottom so as to permit the incoming fluids to pass from the top ofthesettling tank to the bottom, so'that such incoming fluids do notdisturb stratification-which takes place during the course ofdemulsification. The settling tank has two outlets, one being below ,thewater level to drain off the water resulting from de mulsification oraccompanyi'ngthe emulsionf'as free water, the other being anoil outletat'the top to permit the passage of dehydrated oil to a second tank,being 'a storage tank, which holds pipeline @or. dehydrated oil. Ifdesired, 'the pony duit or pipe which serves to carry the fiuids fromthe well to the settling tank may includea'sec tion of pipe with bafflesto serve as a mixer, to insure thorough distribution of the demulsifierthroughout the fluids, or a heater for raisingthe temperature .of thefluids to some convenient temperature, for instance, to F., or bothheater and mixer. I '1, Demul sification procedure is started byfsimplysetting the pump so as to feeda comparatively large ratio ofdemulsifier, for instanca 1:5,000'. As soon as a complete break orsatisfactory demulsification is obtained, the pump is regulated untilexperience shows that the amount ofv demulsifier being added is justsuflicient to produce clean or dehydrated oil; The amount being fed atsuch stage is usually 1210,000, -1:1 5 ,000, 120,000, or the like. v

In many instances the oxyalkylated products herein specified asdemulsifiers can be convenientlyused without dilution. However, aspreviously noted, they may be diluted as desired with any suitablesolvent. For instance, by mix ing 75 parts by weight of an oxyalkylatedderivative, for example, the product of Example 21bwith 15 parts byweightof xylene and 10 parts by weight of isopropyl alcohol, anexcellent demulsi fier is obtained. Selection of the solvent will vary,depending upon the solubility characteristicsof the j-oxyalkylatedproduct, and of course will be dictated in part by economicconsiderations, i. e.

cost.

As noted above, theproducts herein described may be used not only indiluted form, but also may be: used admixed with some other-chemicaldemulsifier." :A mixture which illustrates; such combination is theiollowing:

PART .5

Previous reference has been made to other oxyalkylating agents otherthan propylene oxide, such as ethylene oxide. Obviously variants can beprepared which do not depart from what is herein'but .do producemodifications. The diol"2-methylpentanediol 2g4 can be-reactedwithethyleneoxide in modest amounts and thensub- 'jected to .oxypropylationprovided that the resuiltant derivative "is (a): water-insoluble, (b)kerosene-soluble, and (c) has present to 80 alkylene oxide radicals.Needless to say, in order .to have water-insolubility andkerosene-solubility the large! majority -must be propylene oxide. Othervariants suggest themselves as, for example, replacing .propylene .oxideby .butylene oxide.

More specifically then one mole of Z-methylpentanediol-.2,4 can betreated with 2,4 or 6 moles of ethylene oxide and then treated withpropylene oxide so as to produce a water-:inso'luble, kerosene-solublediol in which there are present 15 to .80 oxide radicals as previouslyspecified. Similarly the propylene oxide can be added first and then theethylene oxide, or random'oxy kylation can be employed using a mixtureofthe two oxides. The compounds so obtained are readily esterified in thesamemanner asidescribed inrPartIZ, preceding. Incidentally, thejdio'lsdescribed in Part 1 or the modifications desc ibed therein can :betreated with various reactants such as glycide, epichlorohydrin, dimethyl sulfate, sulfuric acid, 'maleic anhydride, ethylene imine, etc.If treated with epichlorohydrin or monochloroacetic acid the resultantproduct can "beofurther reacted with a tertiary amine 'such as pyridine,or the like, to give quaternary ammonium compounds. If treated withmaleic anhydride to give a total ester the resultant can be "treatedwith sodium bisulfite to yield-a sulfosuccinate. Sulfo groupscan be introduced also by means of a sulfating agent as previously suggested, orby treating the chloroacetic acid resultant with soduim sulfite.

I have found that it such hydroxylated compound or compounds are reactedfurther so as to produce entirely new derivatives, such new derivativeshave the properties of the original hydroxylated compound insofar thatthey are effective and valuable demulsifying agents for resolution ofwater-in-oil emulsions as found in the petroleum industry, as breakinducers in doctortreatment of sour crude, etc.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent, is:

1. A process for breaking petroleum emulsions of the water-in-oil typecharacterized by subjecting the emulsion to the action of a demulsifierincluding hydrophile synthetic products; said hydrophile syntheticproducts being characterized by the following formula:

in which nand n are numerals including 0 with the proviso that n plus mequals a sum varying from 15 to .80, and 1 .is a whole number not over 2and Risa radicalof the polycarboxy acid.

in which n" has its previous significance; and with the further provisothat theparentfdiol prior to esterification be water-insoluble andkerosenesoluble.

2. A process for breaking petroleum emulsions of the water-in-oil .typecharacterized by :subjecting the emulsion to the action of a.demulsifier including hydrophile synthetic products; said hydrophilesynthetic products being characterized by the following formula:

CH: CH; 0 o

in which n and n are numerals including 0 with the proviso that 11. plusn: equals a sum varying from 15 to 80, and n" is a whole number not over2, and R is a radical of 'thepolycarboxy acid 'C'O OH in which n" hasits previous significance; said 'polycarboxy acid having not more than 8carbon atoms; and with the further proviso that the parent diol prior toesterification be water-insoluble and kerosene -soluble.

3. A process for breaking petroleum emulsions of the water-in-oil typecharacterized by subjecting the emulsion to the action of a demulsifierincluding hydrophile synthetic products; said hydrophile syntheticproducts being characterized by the following formula:

CH3 CH3 in which n and n are numerals excluding 0 with the proviso thatn plus 11/ equals a sum varying from 15 to 80, and n" is a whole numbernot over 2, and R is a radical of the polycarboxy acid COOH (COOHLW inwhich n has its previous significance; said polycarboxy acid having notmore than 8 carbon atoms; and with the further proviso that the parentdiol prior to esterification be water-insoluble and kerosene-soluble.

4. A process for breaking petroleum emulsions of the water-in-oil typecharacterized by subjecting the emulsion to the action of a demulsifierincluding hydrophile synthetic products; said hydrophile syntheticproducts being characterized by the following formula:

9 CH3 CH3 5: E if (HOC)RC(OCaHOHOC-g-gOKhEkOL-(JIMCOOH) said dicarboxyacid having not more than 8 carbon atoms; and with the further provisothat the parent diol prior to esterification be water-insoluble andkerosene-soluble.

5. The process of claim 4 wherein the dicarboxy acid is phthalic acid.

22 6. The process of claim 4 wherein the dicarboxy acid is maleic acid.

7. The process of claim 4 wherein the dicarboxy acid is succinic acid.

8. The process of claim 4 wherein the dicarboxy acid is citraconic acid.

9. The process of claim 4 wherein the dicarboxy acid is diglycollicacid.

MELVIN DE GROOTE.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,507,560 De Groote et al. May16, 1950 2,514,399 Kirkpatrick et al. July 11, 1950 2,562,878 Blair Aug.7, 1951

1. A PROCESS FOR BREAKING PETROLEUM EMULSIONS OF THE WATER-IN-OIL TYPECHARACTERIZED BY SUBJECTING THE EMULSION TO THE ACTION OF A DEMULSIFIERINCLUDING HYDROPHILE SYNTHETIC PRODUCTS; SAID HYDROPHILE SYNTHETICPRODUCTS BEING CHARACTERIZED BY THE FOLLOWING FORMULA: